The photoprotection of keratinous substrates, including both skin and hair, is considered by many to be necessary in order to facilitate protection from sun-damage, sunburn, photo-aging, as well as to decrease the chances of skin cancer development caused by exposure to ultraviolet (“UV”) radiation. There are typically two types of UV-A/UV-B sunscreen compositions used to accomplish photoprotection, namely, inorganic UV filters and organic UV filters.
Inorganic UV filters such as titanium dioxide and zinc oxide are typically employed in large quantities in order to ensure proper coverage/maximum protection over the surface onto which they are applied. As a result, inorganic UV filters have a tendency to cause skin to which they are applied to feel dry, and further impart an undesirable color onto the treated surface (naturally white, but sometimes colored for aesthetic purposes with varying degrees of aesthetic success).
Further, UV filters may either protect against UV-A radiation (long-wave), UV-B radiation (shortwave), or both. In the past, it was commonly held that protection against UV-B radiation was the primary or even sole consideration in sun-protection. However, more recent research has revealed that exposure to UV-A radiation may also be dangerous and lead to undesirable effects. As such, the current trend in sun-protection endeavors is typically to protect against both UV-A and UV-B in a single composition, and to increase both the SPF and the UV-A ratings of the composition.
Sunscreens are treated as over-the-counter “OTC”) products in many jurisdictions, including in the United States of America (“U.S.”), As a result of the classification of sunscreens as OTC products, in the U.S., sunscreen is regulated by the U.S. Food and Drug Administration (“FDA”), which, due to regulatory issues and safety concerns, has limited the active ingredients of sunscreen compositions, such as UV filters, substantially. Thus, there are limited. UV filters available to achieve high efficacy with respect to both SPF and UV-A protection. Most commonly, these UV filters are regarded to include avobenzone, oxybenzone, octisalate, octocrylene, and homosalate.
U.S. Pat. No. 9,050,475 B2 (the '475 patent) discloses methods and compositions for the protection of an object from UV light, which includes multiple photostabilizers but which is essentially free of oxybenzone and oxtinoxate. The '475 patent claims to enhance the SPF by adding antioxidants, photostabilizers and/or film forms. However, the '475 patent does not claim any defined level of UV-A protection. In particular, the '475 patent describes the photostabilization of avobenzone, which is a UV-A filter and which is not itself photostable, however it is not believed that the stabilization of avobenzone, by itself, is capable of enabling a sufficiently high UV-A protection in a composition for current consumer and health requirements and desires.
It is therefore an object of the present invention to provide a composition capable of not only of a defined high SPF rating, but also providing a defined high UV-A rating which has eliminated oxybenzone content.